Study On Wind Load Distribution Characteristics Of Large Span Curved Roof Structure

With the rapid development of science and technology,the wide application of new materials and new technologies,the appearance of building structure s is more large,complex and diversified.Most of these structures have the characteristics of large span and light weight,which makes large span buildings more sensitive to wind loads,so the wind load effect in the large span roof structure must be taken seriously.However,the Load Code for the Design of Building Structures(GB50009-2012)has insufficient wind pressure value and design for complex and large span building structures.This has become an urgent problem for structural designers.In this paper,a large span curved roof structure is taken as the research object.The wind load effect distribution of the building surface is analyzed in detail by the combination of wind tunnel test and Computational Fluid Dynamics(CFD)numerical simulation technology.The wind tunnel test is the most common and effective means of designing wind resistance.In this paper,the B-type wind field is simulated by the method of arranging sharp and rough elements.The experimental results are compared with the average w ind speed profile and turbulence profile curve of the B-type landform,and the wind pressure test of the building surface is tested for the next step.lay the foundation.Wind tunnel test results show that the wind direction angle has a great influence on the wind load distribution of the structural roof.No matter which wind direction angle,the windward pressure coefficient and body shape coefficient of the structure windward surface are pressure.The surface and side are negative,mainly affected by the suction of the wind,and controlled by negative pressure.When the northern section of the roof of the building is at 0°~40° and 320°~360° wind direction,the outer surface will show positive pressure,indicating that the large-span curved floor canopy structure can effectively weaken the wind load and reduce the area of the negative pressure zone of the roof.The Standard k-ε turbulence models,Realizable k-ε and SST k-ω are used to simulate the surface wind pressure of large-span curved roof structures under different wind direction angles,and the two-phase verification is carried out with the actual wind tunnel test results.The verified numerical calculation method analyzes the influence of the scale effect of the large-span curved floor canopy building model on the actual evaluation of wind load under the simplified geometry.The results of CFD simulation show that the general trend of three turbulence models for predicting the flow of building flow is consistent.Compared with the Standard k-ε model,the calculation results of Realizable k-ε and SST k-ω turbulence models are more accurate.For similar buildings,it is suggested to select the SST k-ω or Realizable k-ε turbulence model suitable for complex model calculation.Scale effect has a weak influence on the pressure coefficient of the building surface.If only the pressure distribution of the building surface is considered,the scale effect can be neglected,but scale effect has a significant impact on the flow field distributio n at the tail of the building.Finally,the wind pressure distribution,wind speed vector distribution and wind field trace distribution of the large span curved roof structure are obtained by CFD numerical simulation,and the relationship between the building shape and the wind field flow is further studied.The results show that when the wind acts on the surface of the building,obvious flow separation occurs at the corners,edges and corners,etc.of the building.The incoming and outgoing flows meet to form a stronger wind speed,and a large number of long vortices are formed at the rear.In the long vortex,the eddy currents are interlaced,and the flow state is complex.At the same time,a relatively large recirculation area appears on the leeward side of the structure.By clarifying the relationship between the building shape and the surrounding wind field,the optimized design of the building shape can be realized,and the unfavorable wind direction and wind speed of the structure can be reduced.At the last,the wind load affected by the structure can be weakened.The surface wind pressure and wind field flow study of the above-mentioned structure can provide reference for the wind-resistant design of similar building structures.